| Message ID | 20181230222105.36031-1-willemdebruijn.kernel@gmail.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] tap: call skb_probe_transport_header after setting skb->dev | expand |
From: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Date: Sun, 30 Dec 2018 17:21:05 -0500 > From: Willem de Bruijn <willemb@google.com> > > The BPF flow dissector expects either skb->sk or skb->dev set on > all skbs. Delay flow dissection until after skb->dev is set. > > This requires calling from within an rcu read-side critical section. > That is fine, see also the call from tun_xdp_one. > > Fixes: d0e13a1488ad ("flow_dissector: lookup netns by skb->sk if skb->dev is NULL") > Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> > Signed-off-by: Willem de Bruijn <willemb@google.com> Applied and queued up for -stable.
On 30.12.2018 23:21, Willem de Bruijn wrote: > From: Willem de Bruijn <willemb@google.com> > > The BPF flow dissector expects either skb->sk or skb->dev set on > all skbs. Delay flow dissection until after skb->dev is set. > > This requires calling from within an rcu read-side critical section. > That is fine, see also the call from tun_xdp_one. > > Fixes: d0e13a1488ad ("flow_dissector: lookup netns by skb->sk if skb->dev is NULL") > Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> > Signed-off-by: Willem de Bruijn <willemb@google.com> Already too late, but Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> > --- > drivers/net/tap.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/net/tap.c b/drivers/net/tap.c > index 443b2694130c..c0b52e48f0e6 100644 > --- a/drivers/net/tap.c > +++ b/drivers/net/tap.c > @@ -1177,8 +1177,6 @@ static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp) > goto err_kfree; > } > > - skb_probe_transport_header(skb, ETH_HLEN); > - > /* Move network header to the right position for VLAN tagged packets */ > if ((skb->protocol == htons(ETH_P_8021Q) || > skb->protocol == htons(ETH_P_8021AD)) && > @@ -1189,6 +1187,7 @@ static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp) > tap = rcu_dereference(q->tap); > if (tap) { > skb->dev = tap->dev; > + skb_probe_transport_header(skb, ETH_HLEN); > dev_queue_xmit(skb); > } else { > kfree_skb(skb); >
diff --git a/drivers/net/tap.c b/drivers/net/tap.c index 443b2694130c..c0b52e48f0e6 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -1177,8 +1177,6 @@ static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp) goto err_kfree; } - skb_probe_transport_header(skb, ETH_HLEN); - /* Move network header to the right position for VLAN tagged packets */ if ((skb->protocol == htons(ETH_P_8021Q) || skb->protocol == htons(ETH_P_8021AD)) && @@ -1189,6 +1187,7 @@ static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp) tap = rcu_dereference(q->tap); if (tap) { skb->dev = tap->dev; + skb_probe_transport_header(skb, ETH_HLEN); dev_queue_xmit(skb); } else { kfree_skb(skb);